WO2001045478A1

WO2001045478A1 - Multilayered printed wiring board and production method therefor

Info

Publication number: WO2001045478A1
Application number: PCT/JP2000/008803
Authority: WO
Inventors: Satoshi Maezawa; Masashi Tachibana; Kazuya Oishi
Original assignee: Matsushita Electric Industrial Co. Ltd.
Priority date: 1999-12-14
Filing date: 2000-12-13
Publication date: 2001-06-21
Also published as: US6630630B1; EP1194023A4; EP1194023A1; CN1189068C; CN1337145A; TW506242B

Abstract

A multilayered printed wiring board comprising an insulation substrate (3), an inner layer material (1) having inner layer material-use conductive patterns (2) disposed on the opposite sides of the insulation substrate and formed of metal foils, and interstitial via holes (4) disposed in the insulation substrate, insulation resins (5b) disposed on the opposite sides of the inner layer material, outer layer-use conductive patterns (8) disposed on the surfaces of the insulation resins, and surface via holes (7) for electrically connecting the inner layer material-use conductive patterns with the outer layer-use conductive patterns, wherein the outer layer-use conductive patterns are formed of insulation resin-carrying metal foils (5) having the insulation resins and metal foils (5a) bonded to the insulation resins, whereby providing an excellent wiring housing capability, and dramatically improving the bonding strength between the insulation resins and the outer layer-use conductive patterns to thereby retain an excellent parts-mounting strength even if the outer layer-use conductive patterns are reduced in diameter.

Description

Description Multilayer printed wiring board and method of manufacturing the same

The present invention relates to a multilayer printed wiring board used for various electronic devices and a method for manufacturing the same. Background art

In recent years, as electronic devices such as personal computers, mobile communication telephones, and video cameras have become more sophisticated and denser, electronic components and their core semiconductors have become smaller and more highly integrated. Requires higher speed, higher speed, or more pins.

Along with this, multilayer printed wiring boards require an improvement in wiring accommodation and surface mounting density. Furthermore, as the diameter of the soldering land becomes smaller, there is a demand for improved reliability of the joining strength between the component and the substrate. More specifically, mounting with both high-density and small-diameter land with a diameter of 0.3 mm or less, as typified by a 0.5 mm pitch pole griddle (hereinafter referred to as BGA). There is a demand for printed wiring boards that can cope with such problems. For example, printed wiring boards that have excellent performance against mechanical stress such as drop impact have been demanded.

In order to satisfy these requirements, the following conventional multilayer printed wiring boards have been proposed. Conventional multilayer printed wiring board Includes an inner layer material and a photosensitive resin or film-like insulating layer provided on both sides of the inner layer material. The inner layer material has a resin multilayer printed wiring board, and each layer in the multilayer printed wiring board is electrically connected by an interstitial via hole (IVH). . The photosensitive resin or the insulating layer is formed by coating or laminating on both surfaces of the inner layer material. Non-through holes are formed in the inner layer material, and the layers are electrically connected by metal plating.

The method of manufacturing this conventional multilayer printed wiring board will be described below.

FIG. 3 shows a conventional method for manufacturing a multilayer printed wiring board. In FIG. 3, an insulating layer 12 such as a photosensitive type resin is provided on the outermost layer, and the insulating layer 12 is provided by coating or laminating. This conventional multilayer printed wiring board 15 has a conductive pattern 11 for an outer layer, a resin insulating layer 12, an inner layer material 13, a non-through hole 12 a, a surface via hole (SVH) 11. a. The inner layer material 13 has an insulating substrate 14, a conductive pattern 14 a for the inner layer material, a copper foil 14 d, and a conductive base 14 b for the inner layer material. The insulating substrate 14 is made from a pre-predator 14c force. The self-via hole 11 a is formed by metal plating the non-through hole 12 a formed in the resin insulating layer 12. The non-through hole 12a is formed on the resin insulating layer 12 by an exposure-to-development method, a laser irradiation method, or the like to form a surface via hole 11a. . Multi-layer pre The printed wiring board 15 has conductive patterns inside and outside the multilayer printed wiring board 15. A method for manufacturing the multilayer printed wiring board configured as described above will be described below.

First, in the step (a) in FIG. 3, a hole is formed in the pre-preparer 14c. Fill the formed holes with conductive paste 14b. Thereafter, the copper foil is overlaid on the pre-preparer 14c, and then hot-pressed, whereby the copper foil is bonded to the pre-preparer 14c filled with the conductive paste 14b. In this way, a copper-clad laminate having copper foil on both sides of the insulating substrate 14 is formed. Thereafter, a conductive pattern 14a for the inner layer material is formed by using a known screen printing method or a photographic method. In this way, an insulating substrate 14 having conductive patterns 14a on both sides is formed.

Next, in a step (b) of FIG. 3, a pre-preparer 14c in which holes are filled with a conductive paste 14b is prepared. A pre-predeer 14c filled with the conductive paste 14b is laminated on both sides of an insulating substrate 14 having a conductive pattern 14a on both sides. In addition, a copper foil 14d is laminated on the surface of the pre-preparer 14c filled with the conductive paste 14b. Thereafter, these laminates are heated by a hot press and then pressurized.

Next, in the step (c) of FIG. 3, a known screen printing method or a photographic method is applied to the copper foil 14d set in the step (b). Thus, a conductor pattern 14a is formed on both sides. Thus, (c) of Fig. 3 An inner layer material 13 as shown in FIG.

Next, in step (d) of FIG. 3, a resin insulating layer 12 such as a photosensitive type resin is applied on the inner layer material 13 in a semi-cured state. Alternatively, the resin insulation layer 12 is laminated on the inner layer material 13.

Thereafter, in the step (e) of FIG. 3, a non-through hole 12a is formed at a predetermined position by an exposure and development step or a laser irradiation step.

Next, in step (f) of FIG. 3, a conductive pattern 11 on the resin insulating layer 12 is formed by metal plating, and a surface by-pass is formed in the non-through hole 12a. A hole 11a is formed. The surface via hole 11a has a function of electrically connecting the inner conductive pattern to the outer conductive pattern. Thus, a multilayer printed wiring board 15 is obtained.

After that, the formation of the solder resist and the processing of the outer shape are performed by a known method such as a photographic method.

In the above-mentioned conventional multilayer printed wiring board, the inner layer material has an interstitial via hole (IVH) at an arbitrary position in all layers, and the outer layer has a thickness of about 50 m or more. It has about 100 small non-through holes. As described above, the conventional multilayer printed wiring board has excellent wiring accommodating properties and excellent surface high-density mounting. However, in such a conventional multilayer printed wiring board, the adhesive strength between the outer conductive pattern 14a and the resin insulating layer 12 was weak. In recent years, pitch balls As the grid array becomes more highly integrated and denser, the diameter of the soldering land becomes smaller and the bonding strength between the outer conductive pattern 14a and the insulating substrate 14 is required. Have been. That is, this conventional multilayer printed wiring board 15 has a conductive pattern formed on the resin insulating layer 12 by metal plating. The plating layer formed on the resin by plating has a weak adhesive strength. Therefore, the conductive pattern 11 placed on the resin insulating layer 12 has a weak adhesive force to the resin insulating layer 12. Therefore, when a high-density component is mounted, for example, when soldering is performed on a small-diameter land, the conductor pattern 11 is peeled off from the resin insulating layer 12 due to mechanical stress. There was a risk of separation.

Further, the curing process of the insulating substrate 14 forming the inner layer material 13 is different from that of the insulating layer 12 forming the outermost layer. Therefore, a large difference in physical characteristics between the insulating substrate 14 and the resin insulating layer 12 occurs. Therefore, the adhesion between the inner layer material and the outermost layer is weakened. Alternatively, heat generated during soldering in the component mounting process may cause cracks due to differences in thermal expansion coefficients and peeling between the inner layer material and the outermost layer. .

The present invention improves the bonding strength between the outer conductive pattern and the insulating layer while maintaining the conventional features of the wiring accommodating property and the surface high-density mounting, and improves the 0.5 mm pitch pole grid array (BGA). High integration and high density parts are good for mechanical stress Provide multilayer printed wiring boards with any features that have mounting reliability. Disclosure of the invention

The multilayer printed wiring board of the present invention

(a) An inner layer material having an insulating substrate, a conductive pattern for an inner layer material formed by metal foils provided on both sides of the insulating substrate, and an interstitial via hole provided on the insulating substrate When,

(b) an insulating resin installed on both sides of the inner layer material,

(c) an outer layer conductive pattern provided on the surface of the insulating resin;

(d) a surface via hole for electrically connecting the conductive pattern for the inner layer material and the conductive pattern for the outer layer;

With

The interstitial via hole electrically connects each inner layer conductive pattern of the plurality of inner layer conductive patterns;

The outer layer conductive pattern is formed from the metal foil out of the metal foil with the insulating resin having the insulating resin and the metal foil bonded to the insulating resin.

The method for manufacturing a multilayer printed wiring board according to the present invention includes:

(a) an insulating substrate, and metal foil placed on both sides of the insulating substrate Forming an inner layer material having an inner layer material conductive pattern formed by the above, and an instantaneous via hole provided on the insulating substrate;

(b) laminating a metal foil with an insulating resin having an insulating resin and a metal foil bonded to the insulating resin on both surfaces of the inner layer material,

(C) a step of pressing the inner layer material and the metal foil with insulating resin superposed on both surfaces of the inner layer material while heating,

Here, the insulating resin is adhered to the inner layer material, and (d) forming a non-through hole in the metal foil with the insulating resin by processing the metal foil with the insulating resin, (e) Processing the metal foil exposed on the surface to form an outer layer conductive pattern;

(f) electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern

Is provided.

With this configuration, a multilayer printed wiring board having remarkably excellent wiring accommodation properties can be obtained. Furthermore, the contact strength between the outer layer conductive pattern and the base material is significantly improved. Therefore, high mounting reliability can be realized even in a multilayer printed wiring board having a small diameter land. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a multi-layer print arrangement according to an exemplary embodiment of the present invention. FIG. 3 shows a cross-sectional view of the manufacturing process of the wire plate. FIG. 2 is a cross-sectional view showing a process of manufacturing a multilayer printed wiring board according to another exemplary embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a process of manufacturing a conventional multilayer printed wiring board. BEST MODE FOR CARRYING OUT THE INVENTION

In the multilayer printed wiring board according to one embodiment of the present invention, the inner layer material has an insulating substrate and a conductive pattern for the inner layer material provided on both sides of the insulating substrate. The conductive pattern for the inner layer material of each layer is electrically connected by an interstitial via hole (IVH). On both surfaces of the inner layer material, a metal foil with an insulating resin having a metal foil and an insulating resin having strong adhesiveness to the metal foil is bonded in advance, and these laminates are heated and pressed. Thereafter, a non-through hole is formed in the metal foil with insulating resin. Then, the conductive pattern for the inner layer material and the conductive pattern for the outer layer are electrically connected by metal plating or the like. According to this configuration, a multilayer printed wiring board having remarkably high wiring accommodation capacity can be obtained. Furthermore, since the above-described metal foil with insulating resin is used as the outer layer material, the bonding strength between the insulating resin and the metal foil is dramatically improved. Therefore, good component mounting strength can be maintained even if the outer conductor pattern has a small diameter.

The multilayer printed wiring board according to one embodiment of the present invention comprises: (a) a base material impregnated with a resin having a through hole, and a conductive material filled in the through hole. An inner layer material having a paste and a conductive pattern for the inner layer material formed by a metal foil bonded to both sides of the base material; and (b) a metal with an insulating resin provided on both sides of the inner layer material. A conductive pattern for the outer layer formed from the metal foil of the foil and (c) a non-penetrating hole formed in the metal foil with insulating resin for connecting the conductive pattern for the outer layer and the conductive pattern for the inner layer material. And a face-by-hole. Each of the conductive patterns for the inner layer material provided on both surfaces of the base material is connected to each other by an interstage via hole formed in the through hole. According to this configuration, a remarkably high wiring accommodating property can be obtained. Furthermore, the adhesive strength between the outer layer conductive pattern and the substrate becomes extremely high. As a result, high mounting reliability can be obtained even for small diameter land.

A method for manufacturing a multilayer printed wiring board according to another embodiment of the present invention includes: (a) a step of forming a through hole in a sheet-like resin-impregnated base material; and (b) a conductive paste in the through hole. Filling step,

(c) laminating a metal foil on both sides of the resin-impregnated base material and pressing while heating, and (d) forming a circuit by processing the metal foil, and forming a circuit on both sides of the equipment. A conductive pattern for the inner layer material is formed, whereby the step of forming the inner layer material is performed, and (e) a metal foil with an insulating resin is bonded to the outermost layers on both sides of the inner layer material and heated. (F) providing a non-through hole in the outermost metal foil with insulating resin; and (g) connecting the inner layer material conductive pattern and the outermost metal foil through the non-through hole. Electrically connecting. By this method, it is installed on both sides of the substrate The conductive patterns for the inner layer material are electrically connected by conductive paste formed in the through holes.

Preferably, the non-through holes are formed by laser machining. Desirably, a metal plating is provided in the non-through hole, and the metal plating electrically connects the conductive pattern for the inner layer material and the conductive pattern for the outer layer. With this configuration, the surface via hole of the outer layer can be easily formed on the land of the inner-stear via hole of the inner layer material. Therefore, a remarkably high wiring accommodating property can be obtained.

Desirably, as the insulating resin used for the metal foil with the insulating resin, an insulating resin having strong adhesiveness to metal is used. Particularly desirably, the metal foil with an insulating resin includes a metal foil and an insulating resin applied to the metal foil. With this configuration, the adhesive strength between the outer layer conductor pattern and the insulating resin is improved.

Desirably, the through holes and non-through holes are formed by laser machining. With this method, a small diameter non-through hole can be formed with higher productivity than conventional drilling.

Desirably, when a non-through hole is formed in the outermost metal foil with insulating resin, a portion of the metal foil where the non-through hole is formed is removed in advance. According to this method, it is possible to perform processing with a laser diameter larger than the diameter of the non-through hole. Therefore, it is not necessary to control the positional accuracy of laser processing for each non-through hole, and a small-diameter non-through hole can be formed with high productivity.

Preferably, the conductive pattern for the inner layer material and the conductive pattern for the outer layer The step of electrically connecting and has a step of applying metal plating. This metal plating reduces the resistance value and improves reliability.

Desirably, in the step of forming a non-through hole in the outermost metal foil with insulating resin, a portion of the metal foil where the non-through hole is formed is removed in advance, and a laser beam having a diameter larger than the hole diameter is removed. A hole is formed by laser machining with By increasing the diameter of the laser beam by this method, the deviation of the laser processing from the position previously removed from the metal foil is corrected by absorption. Therefore, the non-through hole is accurately and reliably formed.

Desirably, the resin impregnated in the base material is the same material as the insulating resin of the metal foil with the insulating resin. Particularly preferably, these resins are epoxy resins. With this configuration, warping after reflow in soldering is prevented. Furthermore, delamination is prevented. In addition, heat resistance is improved.

Desirably, the substrate included in the insulating substrate has a compressible porous substrate made of an aromatic polyamide. The resin impregnated in the base material has a thermosetting resin. According to this configuration, the multilayer printed wiring board is reduced in weight. In addition, high heat resistance is improved. Therefore, the reliability of the multilayer printed wiring board is improved. Further, the use of the compressible porous substrate improves the reliability of the connection between the conductor protrusion and the metal foil.

The multi-layer printed wiring board of the present invention is characterized in that: (a) an insulating substrate and a metal foil provided on both sides of the insulating substrate; An inner layer material having a conductive pattern for a layer material and an interstitial via hole provided on the insulating substrate; (b) an insulating resin provided on both sides of the inner material; and (c) an insulating resin provided on both sides of the inner material. And (d) a surface via hole for electrically connecting the conductive pattern for the inner layer and the conductive pattern for the outer layer. The outer layer conductive pattern is formed from a metal foil with an insulating resin having the insulating resin and a metal foil adhered to the insulating resin, and the inner layer material conductive pattern further comprises: A conductor protrusion is electrically connected to the inner layer material wiring pattern, and the conductor protrusion penetrates the insulating substrate and is connected to the outer layer conductive pattern. The conductor protrusion has the function of the interstitial via hole.

Desirably, the insulating substrate is formed by curing a sheet-like resin pre-predeer having a base material and a resin impregnated in the base material. The conductor projection penetrates through the inside of the resin pre-spreader. The insulating resin has a non-through hole. The surface via hole is formed in the non-through hole.

According to another embodiment of the present invention, there is provided a method of manufacturing a multilayer printed wiring board, comprising: (a) forming a conical or pyramid-shaped conductor projection at a predetermined position on a metal foil; and (b) having the conductor projection. The surface and the sheet-like base material impregnated with resin are overlapped, and the metal foil and the resin-impregnated base material are laminated while being heated and pressurized while being heated. And the gold placed on both sides of the substrate (C) processing the metal foil to form an inner-layer conductor circuit as a conductive pattern for the inner-layer material to form an inner-layer material; (d) A step of laminating a metal foil with an insulating resin on the inner layer material; (e) a step of processing a metal foil of the metal foil with an insulating resin to form a conductive pattern for an outer layer; A step of forming a non-through hole in the metal foil layer by laser processing; and (g) a step of installing a surface via hole for connecting the outer layer conductive pattern and the inner layer material conductive pattern. . The conductor protrusion has a function of an interstitial via hole.

With the above configuration, the degree of freedom in designing a multilayer printed wiring board can be increased. Therefore, a multilayer printed wiring board can be manufactured by a simple manufacturing process according to the required specifications.

Preferably, the non-through holes are formed by laser machining. Desirably, a metal plating is provided in the non-through hole, and the metal plating electrically connects the conductive pattern for the inner layer material and the conductive pattern for the outer layer.

With this configuration, the outer surface surface hole can be easily formed on the land of the inner vial in the inner vial vial. As a result, a remarkably high wiring capacity can be obtained. In addition, a remarkably high wiring capacity can be obtained. Furthermore, the adhesive strength between the outer layer conductive pattern and the substrate is extremely high, and high mounting reliability can be realized even in a small-diameter land.

Desirably, conductive protrusions are formed by curing the conductive paste. Is done. With this configuration, a large number of conductor projections can be easily formed by a simple process. Therefore, the projection shape becomes uniform and stable. As a result, a multilayer printed wiring board having stable interstitial via holes can be obtained.

Desirably, as the insulating resin used for the metal foil with the insulating resin, an insulating resin having strong adhesiveness to metal is used. Particularly desirably, the metal foil with insulating resin has a metal foil and an insulating resin applied to the metal foil. With this configuration, the adhesive strength between the outer layer conductor pattern and the insulating resin is improved.

Hereinafter, typical embodiments of the present invention will be described with reference to the drawings. Typical Example 1

FIG. 1 is a cross-sectional view illustrating a method for manufacturing a multilayer printed wiring board according to Exemplary Embodiment 1 of the present invention. In FIG. 1, a multilayer printed wiring board 9 includes an inner layer material 1, a metal foil with insulating resin 5, a conductive pattern 8 for an outer layer, and a surface via hole (SVH) 7. The inner layer material 1 has an inner layer material insulating substrate 3, an inner layer material conductive pattern 2, and an inner layer material conductive paste 4. The metal foil 5 with an insulating resin has an insulating resin 5b and a metal foil 5a. The metal foil with insulating resin 5 has a non-through hole 6, and the non-through hole 6 is formed on the metal foil with insulating resin 5 by laser processing. The surface via hole (SVH) 7 has a metal plating formed in the non-through hole 6. Interstitial Jalva Hall (IVH) is formed in inner layer material 1. The surface via hole (SVH) 7 is formed in the outer layer. Each of the layers has a conductive pattern 2.

A method for manufacturing the multilayer printed wiring board configured as described above will be described below.

First, a resin pre-paeder 3 as an insulating substrate for an inner layer material is prepared. The resin pre-printer 3 has an aramide non-woven fabric base material and an epoxy resin impregnated in the aramide non-woven fabric base material. This resin prepreg has a sheet shape, is in a semi-cured state, and has compressibility. That is, the base material is porous and has compressibility. Aramid fibers are fibers made from aromatic polyamides.

Next, as shown in FIG. 1 (a), a through hole is formed in the resin pre-paeder 3a by a carbon dioxide laser process. The conductive paste 4 a is filled in the through hole. The through hole filled with the conductive paste forms an interstitial via hole. After that, copper foil is superimposed on both sides of the resin pre-reader 3a. In this way, a copper-clad laminate before hardening is prepared. Thereafter, the pre-cured copper-clad laminate is pressurized while being heated by a hot press to bond the copper foil to the resin pre-paider 3a and to cure the resin pre-paeder 3a. In this way, a copper-clad laminate having the inner layer insulating substrate 3a and the copper foil bonded to both sides of the insulating substrate 3a is prepared. Next, screw the copper foil of the copper-clad laminate To form the first conductive pattern 2a for the inner layer material. The conductive patterns 2a for the first inner layer material formed on both sides of the insulating substrate 3a are electrically connected to each other by an in-situ via hole having a conductive base.

Next, another uncured copper-clad laminate is superimposed on the insulating substrate 3a having the first inner layer material conductive pattern 2a. The other uncured copper-clad laminate has a resin pre-breg 3 having a through-hole, a conductive paste 4 b filled in the through-hole, and a copper foil superimposed on the resin pre-breg 3 b. Then, the other uncured copper-clad laminate is hot-pressed to bond the copper foil to the resin pre-paider 3b and to cure the resin pre-paeder 3b. Next, the copper foil placed outside is processed by a processing method such as a screen printing method or a photographic method to form the second inner layer material conductive pattern 2b. In this way, an inner layer material 1 as shown in FIG. 1 (a) is prepared. The plurality of conductive patterns, such as the first inner layer material conductive pattern 2a and the second inner layer material conductive pattern 2b, are electrically connected to each other by an in-situ stationary via hole having a conductive base. Connected.

Next, in (b) of FIG. 1, a metal foil 5 with an insulating resin is laminated on both sides of the inner layer material 1. Desirably, the metal foil with insulating resin 5 has a metal foil 5a and an insulating resin 5b. Desirably, the metal foil 5 with an insulating resin has a metal foil 5a and a semi-cured insulating resin 5b applied to the metal foil 5a. Absolute The edge resin 5b has a strong adhesive strength to the metal foil 5a. The laminated inner layer material 1 and the metal foil 5 with insulating resin are pressurized while being heated by a hot press. In this manner, the metal foil 5 with the insulating resin is bonded to the inner layer material 1 and the insulating resin 5b is cured.

In this step, prior to the lamination of the inner layer material 1 and the metal foil 5 with insulating resin, the surface of the first inner layer material conductive pattern 2a of the inner layer material 1 or the copper foil in the previous step is replaced with the surface. It is desirable to apply a surface treatment such as a roughening treatment, a protection treatment, or a baking treatment. As the surface roughening treatment, soft etching or the like is used. As a result, the adhesion between the first inner layer material conductive pattern 2a and the metal foil 5 with insulating resin is significantly improved. Furthermore, the internal stress caused by the difference in thermal shrinkage between the inner layer material 1 and the outermost metal foil with insulating resin 5 is reduced. As a result, the occurrence of cracks is prevented. Further, separation of the inner layer material 1 and the metal foil 5 with insulating resin is prevented.

More desirably, the insulating resin 5b of the metal foil with insulating resin 5 has the same resin material as the resin material used for the above-described insulating substrates 3a and 3b for the inner layer material. That is, the insulating resin 5b has the same epoxy resin. With this configuration, the difference in the internal stress described above is significantly reduced, and as a result, the effect of preventing the occurrence of cracks and peeling is significantly improved.

Desirably, amide fibers are used as the base material of the insulating substrates 2a and 2b for the inner layer material. The reason is as follows. (1) When a conventional paper base and phenolic resin, epoxy resin or polyester are used as the substrate for the inner layer material, a laser processing step for forming through holes In this case, it is difficult to accurately form a desired small hole of about 30 / zm to about 100 m. Therefore, the use of paper base is not practical from the viewpoint of productivity.

(2) Aramid nonwoven fabric has excellent laser processability. That is, compared to an insulating substrate using paper or a glass fiber non-woven fabric or a glass fiber woven fabric, the insulating substrate using the non-woven fabric base material has a force of about 30 m by laser processing.

A small through hole having a diameter of about 100 m can be accurately formed, and the filling operation can be stably performed in the step of filling the through hole with the conductive paste. In addition, the insulating substrate using the aramide non-woven fabric substrate has a smaller diameter hole of about 30 m to about 100 m than the insulating substrate using the glass fiber woven fabric substrate. The conductive paste can be filled accurately.

(3) Even if it was possible to form a small non-through hole with a diameter of 30 to 50 im in the outermost layer of the surface layer, even if the inner layer material had a diameter of 30 to 50 m, If a small-diameter through hole cannot be formed, the wiring accommodation of the multilayer printed wiring board cannot be improved. On the other hand, the base material of the insulating substrates 3a and 3b must be made of an aluminum substrate. When a non-woven fabric made of fiber is used, it is possible to accurately form a small diameter hole of about 30 to about 100, and to fill the through hole with a conductive paste accurately. Can be. (4) Since the metal foil 5 with insulating resin is provided as the outermost layer, it is necessary to reduce the effect of thermal stress generated at the boundary between the outermost layer and the inner layer material. Since the aramide fiber has high mechanical strength, high heat resistance temperature, excellent physical properties, and excellent compressibility, it is used as the base material of the inner layer material. Thus, the effect of thermal stress generated at the boundary between the outermost layer and the inner layer material is reduced. As a result, a multilayer printed wiring board suitable for practical use is obtained.

(5) The nonwoven fabric of amide fiber has excellent compressibility. Usually, as in the present exemplary embodiment, the inner layer material is formed by applying pressure while heating, and thereafter, the metal foil 5 with insulating resin is laminated on both surfaces of the inner layer material, and further heated. Internal stress is generated in the process of repeating the heating and pressurizing heat press processes multiple times such as pressurizing. However, when a pre-preda having an aramide non-woven fabric substrate is used as in the present exemplary embodiment, the internal stress is reduced even in a plurality of compression steps such as heating and pressing. It becomes possible to do. Further, the conduction resistance between the conductive pastes 4a and 4b of the inner layer material 1 and the conductive patterns 2a and 2b of the copper foil can be reduced.

Next, in (c) of FIG. 1, a photosensitive etching resist is applied to the entire surface of the metal foil 5 with an insulating resin, exposed, developed, and developed. As a result, the photosensitive etching resist in the portion where the non-through hole is to be formed is removed. Then, the metal foil 5 where the outermost non-through hole is formed is etched with an etchant such as cupric chloride. Remove with a cleaning solution in advance. Then, a hole having a diameter 5 to 10% larger than a desired diameter of the hole is formed by a laser beam. In this way, a non-through hole 6 is obtained.

Thereafter, the inside of the non-through hole 6 is treated with a permanganic acid solution or the like to remove the exposed resin on the surface of the metal foil of the inner layer material 1. This process is performed a plurality of times as necessary.

Next, in (d) of FIG. 1, a metal plating layer such as an electroless plating or an electric plating is provided on the entire surface of the metal foil 5 a having the non-through holes 6. At this time, the metal plating is also formed in the non-through holes 6. Thereafter, a surface via hole (SVH) 7 and an outer layer conductive pattern 8 are formed by a method such as a screen printing method or a photographic method. Thus, the multilayer printed wiring board 9 is obtained. Further, the inner layer material conductive patterns 2a and 2b and the outer layer conductive pattern 8 are electrically connected by the metal plating layer. In this way, a surface via hole (SVH) 7 is formed.

In the present exemplary embodiment, when the hole diameter of the non-through hole is 30 to 50 ^ m, the metal plating layer 5c installed in the non-through hole is formed by the metal plating layer itself. It is also possible to bury it. When the diameter of the non-through hole is 50 to 100 mm, about 50% of the inside of the non-through hole is buried. Thereby, the adhesive strength between the surface via hole 7 and the insulating resin layer 5b can be increased. In addition, the surface via hole (SVH) 7 is used to form a soldering land for component mounting. It can also be used as a body pattern. As a result, the density of component mounting is increased.

In the present exemplary embodiment, the inner layer material includes a plurality of insulating substrates and a plurality of conductive patterns for the inner layer material. However, the present invention is not limited to this configuration, and the inner layer material may include one insulating substrate and its insulating substrate. It is also possible to have a configuration having the conductive pattern for the inner layer material installed on both sides. Typical Example 2

A more specific embodiment of the present invention will be described below with reference to FIG. 1 described in the first exemplary embodiment.

In FIG. 1, the interstitial via hole (IVH) formed in the inner layer material has a conductive base instead of a metal plating. Therefore, the land formed in the interstitial vial portion has excellent smoothness. Therefore, through the non-through hole 6 of the metal foil 5 with insulating resin from the outer layer, the surface by hole metal (SVH) 7 made of metal plating can be easily placed on this smooth land. Can be formed. Epoxy resin was used as the insulating resin 5b in the metal foil 5 with the insulating resin. On the other hand, as a comparative example, an insulating layer as an outermost layer was formed on both sides of the inner layer material, and then a non-through-hole surface via hole (SVH) and a conductive pattern for the outer layer were formed on a metal sheet. Formed by g. In this way, a multilayer printed wiring board of a comparative example was prepared. Created according to this exemplary embodiment Between the insulating layer 5b and the metal plating 5c at the surface via hole (SVH) between the multilayer printed wiring board prepared and the multilayer printed wiring board prepared by the method of the comparative example. The adhesive strength of the sample and the adhesive strength between the insulating layer 5b and the outer layer conductive pattern 8 were measured and compared. The results are shown in Table 1.

In addition, five samples of this example were prepared as the number of samples used for the test, and five samples of comparative examples were prepared. As a test method, a solder ball is melted in a designated land portion, and then rapidly cooled. Then, a solder pole is pulled at a moving speed of 200; amZ sec. In this state, the tensile strength was measured.

In Table 1, the adhesive strength of the multilayer printed wiring board produced by the method of the present exemplary embodiment is determined by comparing the insulation layer 5b and the metal plating of the surface via hole (SVH). With The adhesive strength between the insulating layer 5b and the conductive pattern 8 for the outer layer is about the same as that of the multilayer printed wiring board prepared by the method according to the comparative example. It has an intensity ranging from 2 to about 5 times.

Further, in the present exemplary embodiment, the method of applying pressure while heating the semi-cured insulating resin by heating with a hot press is to apply or laminate the conventional insulating resin on the surface of the inner layer material. It has less variation in the outermost layer coating process than the method and excellent surface flatness.

Furthermore, if the same resin as that of the resin pre-paider of the insulating board is used as the insulating resin 5b of the metal foil 5 with the insulating resin, the post-reflow of the multi-layer printed wiring board is not required. No heat resistance, delamination, etc. were observed at all. Particularly preferably, the resin is an epoxy resin.

As described above, the multilayer printed wiring board of the present exemplary embodiment has remarkably excellent wiring accommodating properties. Further, the adhesive strength between the insulating layer and the surf-aspire hole (SVH) and the adhesive strength between the insulating layer and the outer layer conductive pattern are significantly improved. Furthermore, in component mounting in a small-diameter land, accurate component mounting can be performed, and high reliability can be obtained. Typical Example 3

Manufacturing method of multilayer printed wiring board according to another exemplary embodiment of the present invention Figure 2 shows the process. In particular, a method of forming an inner layer material different from the above-described exemplary embodiment 1 will be described.

In the step (a) of FIG. 2, a conical or pyramid-shaped conductor projection 22 is formed at a predetermined position of the copper foil 2la as a conductive metal foil by a printing method or a transfer method. Desirably, the conductor protrusion 22 is formed of a conductive base.

In step (b) of FIG. 2, a resin pre-bleg 23 as an insulating substrate for the inner layer material is prepared. The resin pre-bleg 23 has a nonwoven fabric base material of an amide fiber and an epoxy resin impregnated in the base material. This resin pre-breg 23 is in a semi-cured state. The first copper foil 21 b is superimposed on the front surface of the resin pre-breg 23, and the first copper foil 21 a having the conductor protrusion 22 is superimposed on the back surface of the resin pre-breg 23.

In (c) of FIG. 2, the first copper foil 2la having the above-mentioned conductor protrusion 22, the resin pre-breg 23 and the second copper foil 2lb are pressed in a heated state. As a result, the conductor protrusion 22 penetrates the resin pre-preg 23, and the first copper foil 2la, the resin pre-preg 23 and the second copper foil 2lb are adhered to each other. Then, the resin prepreg 23 is cured to form the insulating substrate 23. In this way, an inner layer laminate 24 is prepared.

Then, in step (d) of FIG. 2, the first copper foil 2 la is added to form the first inner layer conductive pattern 25 a, and the second copper foil 21 b is processed. A conductive pattern 25b for the inner layer material is formed. The conductive pattern 25a for the first inner layer material is the conductor for the first inner layer material. Circuit 25a, and the second inner layer material conductive pattern 25b is a second inner layer material conductor circuit 25b. In this way, the inner layer conductor circuit 25 is formed on the inner layer laminated board 24.

Thereafter, the metal foil with insulating resin 5 is laminated by the same method as the step (b) in FIG. 1 of the typical embodiment 1. The metal foil with insulating resin 5 has a metal foil 5a and a semi-hardened insulating resin 5b applied to the metal foil 5a. The inner layer laminate 24 and the metal foil with insulating resin 5 are pressurized while being heated by a hot press. In this way, the metal foil 5 with insulating resin is bonded to the inner layer laminated plate 24 and the insulating resin 5b is cured. Then, the same processes as (d) and (d) are added to the process shown in Fig. 1. In this way, a multilayer printed wiring board is formed.

Note that the multilayer printed wiring board of this exemplary embodiment 3 is composed of the first inner layer conductive pattern 25a and the second inner layer material conductive pattern, which are provided on both sides of one inner layer laminate 24. However, the present invention is not limited to this configuration, and a multilayer printed wiring board having a plurality of inner layer material laminates 24 can also be manufactured. That is, an inner layer material having a plurality of inner layer material laminated plates 24 is prepared by the same method as the step (a) in FIG. 1 shown in the typical example 1. Further, by repeating the steps (b) and (c) in FIG. 2, the inner laminate can have a multilayer structure. By adopting the method of the typical embodiment 1 to the typical embodiment 3, a simple manufacturing process can be performed in accordance with the required specifications, and thus, many processes can be performed. It becomes possible to build a multilayer printed wiring board. Further, the multilayer printed wiring board of the present exemplary embodiment has remarkably excellent wiring capacity. Furthermore, the contact strength between the outer layer conductive pattern and the substrate is significantly improved. Therefore, high mounting reliability can be realized even in a multilayer printed wiring board having a small diameter land. Industrial applications

In the structure of the present invention, since the inner layer material has an interstitial via hole (IVH) formed by the conductive paste, the land of the inner layer material interstitial via hole (IVH) is reduced. A land portion can be formed so as to have smoothness. The surface via holes (SVH) can be easily formed on the land by the metal plating from the outer layer, so that the wiring accommodating property is significantly improved. In addition, the insulating resin used in the metal foil with the insulating resin has strong adhesiveness to the metal, so that the adhesive strength between the insulating resin and the metal foil is dramatically improved. Good component mounting strength can be maintained even if the conductive pattern has a small diameter.

Claims

(a) an insulating substrate; a plurality of conductive patterns for inner layer materials formed by metal foils provided on both sides of the insulating substrate; and an interstitial device provided on the insulating substrate.

(B) an insulating resin provided on both sides of the inner layer material, (c) an outer layer conductive pattern adhered to the insulating resin, and (d) the inner layer material conductive pattern. And the conductive pattern for the outer layer.

And a surface via hole for electrically connecting the inner layer conductive pattern to each of the plurality of inner layer conductive patterns. The surface via hole electrically connects each inner layer conductive pattern of the plurality of inner layer conductive patterns. The outer layer conductive pattern is a multilayer print formed from the metal foil of the metal foil with the insulating resin having the insulating resin and the metal foil adhered to the insulating resin. Wiring board.

2. The insulating substrate according to claim 1, wherein the insulating substrate is formed by curing a sheet-shaped resin pre-prepared material having a base material and a resin impregnated in the base material. It has a through hole,

The institial via hole is the through hole Having a conductive paste filled in,

The insulating resin has a non-through hole,

The multi-layer printed wiring board, wherein the surface via hole is formed in the non-through hole.

3. In claim 1,

The surface via hole is a multilayer printed wiring board having a metal plating formed in the non-through hole. 4 In claim 1 of the claims,

The surface via hole has a metal plating formed in the non-through hole,

The multi-layer printed wiring board further includes a metal plating provided on a surface of the outer layer conductive pattern.

5. In claim 2,

A multilayer printed wiring board, wherein the resin contained in the insulating substrate has the same material as the insulating resin.

6. In claim 2,

The resin contained in the insulating substrate has a thermosetting resin,

The substrate is made from an aromatic polyamide and is compressible. And a multi-layer printed wiring board having porosity.

The above-mentioned base material is a multilayer printed wiring board having a nonwoven fabric made of aromatic polyamide fibers. In claim 1 of the claims,

At least one of the non-through hole and the through hole is a multilayer printed wiring board having a diameter of about 30 to about 100 m. In claim 1 of the claims,

The multilayer printed wiring board, wherein the non-through holes and the through holes are holes formed by laser processing. 0. In claim 1 of the claims,

The multilayer printed wiring board, wherein the inner layer material includes: a plurality of insulating substrates; and a plurality of inner layer material conductive patterns provided on both sides of each of the plurality of insulating substrates. 1. (a) An inner layer having: an insulating substrate; a conductive pattern for an inner layer material formed by metal foil provided on both sides of the insulating substrate; and an interstitial via hole provided on the insulating substrate. Materials and (b) an insulating resin installed on both sides of the inner layer,

(c) An outer layer conductive pattern installed on the surface of the insulating resin.

—

(d) The conductive pattern for the inner layer material and the conductive butter for the outer layer

A surface via hole that electrically connects the

With

The outer layer conductive pattern is formed from a metal foil with an insulating resin having the insulating resin and a metal foil adhered to the insulating resin,

The conductive pattern for the inner layer material further has a conductive protrusion electrically connected to the wiring pattern for the inner layer material, and the conductive protrusion penetrates the insulating substrate to form the outer layer conductive pattern. Connected to

The conductor projection is a multilayer printed wiring board having the function of the interstitial via hole. In claim 11 of the claims,

The insulating substrate is formed by curing a sheet-like resin pre-predeer having a base material and a resin impregnated in the base material, the conductor protrusion penetrates through the resin pre-predeer, and the insulating resin Has a non-through hole,

The surface via hole is a multilayer printed wiring board formed in the non-through hole.

13. In claim 11 of the Claims,

The multilayer printed wiring board, wherein the non-through holes are holes formed by laser processing.

14. In claim 11 of the Claims,

The multilayer printed wiring board, wherein the conductive protrusions are formed by curing a conductive paste. 15. In claim 11 of the Claims,

The multilayer printed wiring board, wherein the conductor protrusion has at least one of a conical shape and a pyramid shape.

16. In claim 11 of the Claims,

The surface via hole is a multilayer printed wiring board having a metal plating formed in the non-through hole.

17. In paragraph 12 of the Claims,

The surface via hole has a metal plating formed in the non-through hole,

The multi-layer printed wiring board further includes a metal plating provided on a surface of the outer layer conductive pattern. (a) An inner layer material having an insulating substrate, an inner layer material conductive pattern formed of metal foil provided on both sides of the insulating substrate, and an interstitial via hole provided on the insulating substrate. The process of creating,

(b) a step of superposing a metal foil with an insulating resin having an insulating resin and a metal foil adhered to the insulating resin on both surfaces of the inner layer material,

(c) a step of pressing while heating the inner layer material and the metal foil with insulating resin superposed on both surfaces of the inner layer material, wherein the insulating resin is bonded to the inner layer material,

(d) forming a non-through hole in the metal foil with insulating resin by processing the metal foil with insulating resin;

(e) processing the metal foil to form a conductive pattern for the outer layer before being exposed to the surface,

(f) a step of electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern.

A method for manufacturing a multilayer printed wiring board comprising the method according to claim 18, wherein:

The step of creating the inner layer material,

(i) a step of forming a through-hole in a sheet-shaped resin pre-predeer having a base material and a resin impregnated in the base; (ii) a step of filling the through-hole with a conductive paste, (iii) a step of laminating a metal foil on both surfaces of the resin pre-printer having the conductive paste,

(iv) a pressing step while heating the resin pre-spreader and the metal foil having the conductive paste superimposed thereon, wherein the insulating substrate is formed by curing the resin pre-spreader; The substrate and the metal foil are adhered to each other, and the interstitial via hole is formed by curing the conductive paste.

(V) processing the metal foil to form the conductive pattern for the inner layer material;

A method for producing a multilayer printed wiring board having: 20. In claim 19,

The method for manufacturing a multilayer printed wiring board, wherein the through hole and the non-through hole are formed by laser processing.

2 1. In claim 19,

The step of forming the non-through hole,

Removing the metal foil in a region where the non-through hole is to be formed in advance;

A method for manufacturing a multilayer printed wiring board, comprising a step of forming the non-through hole at a position where the metal foil is removed.

22. In claim 18 of the claim,

The step of electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern includes a step of installing a metal plating in the non-through hole.

23. In paragraph 18 of the Claims,

The step of forming the non-through hole in the metal foil with the insulating resin,

Irradiating a laser beam having a diameter larger than a desired hole diameter to a position where the metal foil is removed, thereby forming the non-through hole;

A method for producing a multilayer printed wiring board having:

24. In claim 19,

The resin contained in the insulating substrate is a multilayer printed wiring board having the same material as the insulating resin of the metal foil with the insulating resin.

25. In claim 19,

The resin contained in the insulating substrate has a thermosetting resin, The method for producing a multilayer printed wiring board having compressibility and porosity, wherein the base material is made of an aromatic polyamide.

26. In claim 19,

A method for producing a multilayer printed wiring board, wherein the substrate has a nonwoven fabric made of aromatic polyamide fibers.

27. In claim 18 of the claim,

Electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern,

Installing a metal plating in the non-through hole;

Providing a metal pattern on the surface of the outer layer conductive pattern. 2 8. In paragraph 19 of the Claims,

At least one of the non-through hole and the through hole is a method for manufacturing a multilayer printed wiring board having a diameter of about 30 zm force to about 100 m. 2 9. In claim 18,

The step of forming the inner layer material includes a step of forming a plurality of insulating substrates, and a plurality of inner layer material conductive patterns provided on both sides of each of the plurality of insulating substrates. Manufacturing method of printed wiring boards.

30. (a) An inner layer having an insulating substrate, a conductive pattern for an inner layer material formed of metal foil provided on both sides of the insulating substrate, and an interstitial via hole provided on the insulating substrate. The process of creating the material,

(b) Insulating resin and the insulating resin on both surfaces of the inner layer material

A step of laminating a metal foil with an insulating resin having a bonded metal foil,

(c) the inner layer material and the inner layer material

A step of applying pressure while heating the metal foil with insulating resin, wherein the insulating resin is bonded to the inner layer material, and (d) processing the metal foil with insulating resin.

Forming a non-through hole in the metal foil with insulating resin; (e) processing the metal foil exposed on the surface to form a conductive pattern for an outer layer;

(f) a step of electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern

With

The step of creating the inner layer material,

(i) a step of placing a conductor projection on the first metal foil;

(ii) a step of preparing a resin pre-spreader having a base material and a resin impregnated in the base material;

(iii) The metal foil having the conductor protrusions is overlapped on one surface of the resin pre-spreader, and the second metal foil is provided on the other surface. And the process of stacking

(iv) The stacked first metal foil, the insulating substrate, and the second metal foil are pressurized while being heated, whereby the conductor protrusion penetrates through the resin pre-spreader, and Forming the insulating substrate by curing the resin pre-predeer, and forming the interstitial via hole by the conductor protrusions;

A method for producing a multilayer printed wiring board having:

31. In paragraph 30 of the Claims,

A method for manufacturing a multilayer printed wiring board, wherein the conductive protrusion has at least one of a conical shape and a pyramid shape. 32. In claim 30 of the claims,

The method for manufacturing a multilayer printed wiring board, wherein the non-through holes are formed by laser processing.

33. In paragraph 30 of the Claims,

The step of electrically connecting the outer layer conductive pattern and the inner layer material conductive pattern includes a step of installing a metal plate in the non-through hole.

34. In Section 30 of the Claims, The resin contained in the insulating substrate has a thermosetting resin,

The method for producing a multilayer printed wiring board having compressibility and porosity, wherein the substrate is made of an aromatic polyamide. In claim 30 of the claims,

The method for producing a multilayer printed wiring board, wherein the non-through holes have a diameter of about 30 to about 100 m.